I have had these types of problems for years. I have had those intense spinning ones that have woken me up but(knock on wood...) they go away fast. I started to think that maybe it had to do with my blood pressure crashing while I was sleeping and my body spewing adrenaline or something to correct it. However, sometimes, I get other types that last for longer periods of time and sometimes I am off balance for days or more. I have been told two things that make some sense, atypical migraine and Benign Positional Vertigo. I do not get headaches often, however, I have been assured by some very good neurologists that vestibular migraine and it's symptoms do not have to include head pain and the symptoms can come and go and don't always need to progress into the path of a typical migraine. I have had some MRI's that have shown signs(punctate foci) that I have migraines and I have had abnormal EEGs that show that I am either prone to migraines or epilepsy(the doctors seem to rule out epilepsy) but I'm finally going to see a neurologist who specializes in dysautonomia and I am very excited to see if these are things he has seen in his past POTS patients(say that one ten times fast ;-) I also tend to get BPV once in a while and that will be a different dizzy/of balance feeling, It is more continuous and can last for days weeks months...This of course is all on top of, or including, normal POTS dizziness/faintness! Needless to say, dizziness was one of the first things that brought me to the doctors, all those years ago. I'm glad you brought this topic up and I will be watching to see if anyone else has more insights into this stuff!